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utils/xgboost_stream.h

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+#ifndef _XGBOOST_STREAM_H_
+#define _XGBOOST_STREAM_H_
+
+#include <cstdio>
+/*!
+ * \file xgboost_stream.h
+ * \brief general stream interface
+ * \author Tianqi Chen: tianqi.tchen@gmail.com
+ */
+namespace xgboost{
+    namespace utils{
+        /*! \brief interface of stream I/O, used to serialize tensor data */
+        class IStream{
+        public:
+            /*! 
+             * \brief read data from stream
+             * \param ptr pointer to memory buffer
+             * \param size size of block
+             * \return usually is the size of data readed
+             */
+            virtual size_t Read( void *ptr, size_t size ) = 0;        
+            /*! 
+             * \brief write data to stream
+             * \param ptr pointer to memory buffer
+             * \param size size of block
+             */
+            virtual void Write( const void *ptr, size_t size ) = 0;
+            /*! \brief virtual destructor */
+            virtual ~IStream( void ){}
+        };
+
+        /*! \brief implementation of file i/o stream */
+        class FileStream: public IStream{
+        private:
+            FILE *fp;
+        public:        
+            FileStream( FILE *fp ){
+                this->fp = fp;
+            }
+            virtual size_t Read( void *ptr, size_t size ){
+                return fread( ptr, size, 1, fp );
+            }
+            virtual void Write( const void *ptr, size_t size ){
+                fwrite( ptr, size, 1, fp );
+            }
+            inline void Close( void ){
+                fclose( fp );
+            }
+        };
+    };
+};
+#endif